This invention relates in general to composite articles and in particular to a lightweight composite article with controlled biodegradation that may be used, for example, as a mulch in the agriculture, horticulture and/or forestry industries.
Plastic mulches are widely used in numerous agricultural applications to control weeds, retain moisture in the soil and increase soil temperature to facilitate plant growth and to increase crop quality and yield.
Some characteristics of a mulch may include having sufficient mechanical strength so that they may be used in commercial farming operations with heavy duty equipment, resistance to stresses caused by weather (rain, sun, wind, etc.), puncture resistance to growing weeds, sufficient wet strength, moisture retention and/or ultraviolet light absorption. Another characteristic is the ability of the mulch to be tilled into the soil by agricultural equipment at the end of the growing season.
A wide variety of mulch products have been developed. Traditionally, agricultural mulch films have been predominantly comprised of either low or high density polyethylene because they are relatively inexpensive and more resistant to severe weather conditions than other materials. However, these materials are not considered biodegradable so they are removed and land filled at the end of the growing season.
To address the biodegradability problem some mulches are made from paper. However, paper alone generally degrades too quickly, does not retain sufficient ground moisture or lacks sufficient strength to be used in commercial agricultural operations. Mulches have also been produced from paper coated with various polymer materials to increase their strength and slow their degradation rate, but the coated paper mulches have not been totally successful.